Monday, April 11, 2005

Some Broccoli Each Day Keeps Serious Troubles Away

The buzzwords several years ago were "functional foods," referring to the health benefits derived from certain foods. What a concept -- food as "medicine." In particular, entries on the "food-is-good-for-you" list include apples and cruciferous vegetables -- broccoli, brussels sprouts, cauliflower, cabbage, bok choy and kale. According to several new studies (as well as some older ones), these foods are particularly helpful for fighting certain types of cancer.
Did you know that apples -- those delicious, versatile, beautiful fruits -- actually are "natural born cancer cell killers" and more, too? Researchers at the French National Institute for Health and Medical Research in Strasbourg exposed cancer cells to apple antioxidants. They found that one type of antioxidant that is prominent in apples, procyanidins, was particularly effective in triggering cancer cell deaths. The French team then did a second-stage study for which they exposed laboratory rats to colon-cancer-causing substances and then fed one of two groups of rats the apple procyanidins for six weeks. The rats that fed on the antioxidant developed half as many precancerous lesions as the group on regular feed. An earlier cell culture study at Cornell University also demonstrated that apple extract inhibited colon cancer cells, but this study reports that the effectiveness seems to come from not just one, but all antioxidants contained in apples, especially those in the skin. A recent Cornell review of the literature on apple research showed that apples also are protective against several other types of cancer, as well as cardiovascular disease and asthma.
The most recent study on the curative effects of foods involved cruciferous vegetables. Researchers at the Mayo Clinic compared diets of 450 men and women, ages 20 to 74, who had non-Hodgkin's lymphoma (NHL) with the diets of a group of healthy people. The study found that the cancer-free group ate a diet rich in green, leafy vegetables and vegetables in the cruciferous group. When a research team from the Harvard School of Public Health did an earlier survey of the 88,410 women in the ongoing Nurses' Health Study, they found that the women who ate more fruits and vegetables generally had a lower risk for NHL, and that those who ate at least five servings of cruciferous vegetables a week reduced the risk for NHL by a full 33%.
This is all very interesting, of course, and indeed inspired me to rush to the green grocer to load up. But first I decided to check in with nutritionist Jane Higdon, PhD, research associate at the Linus Pauling Institute in Corvallis, Oregon, where she studies the function and role of vitamins, minerals and phytochemicals in human health. Dr. Higdon agreed that science is constantly fine-tuning conclusions about specific groups of foods and nutrients that affect health, and she says we can expect to see more of this in the future. She adds that scientists are finding cruciferous vegetables especially intriguing because these are rich in certain phytochemicals that seem to increase the activity of enzymes that detoxify the body. As for apples, they indeed contain many nutrients, fiber and flavonoids, but a big reason they are the focus of so much research, she says, is that they are a common food that many people eat, and so make for easier studying. However, she qualifies this by pointing out that cancer is not just one disease but rather a number of different ones with a common thread. Given this, it makes sense that some foods will affect certain types of cancers and not others. Whether certain varieties of apples pack a more potent punch than others remains to be seen. Dr. Higdon is quick to approve of eating apples and cruciferous vegetables, but she is cautious about jumping on the research-results bandwagon, based on studies thus far. She basically dismisses all cell culture studies because she says they are far removed from what actually happens in the human body. Reason: As the body metabolizes nutrients, it dilutes the concentration of a flavonoid, making it not at all akin to what researchers put into cancer cells in the lab. Complicating the picture further, there are a number of genotypes among people, and individual response to some nutrients and plant chemicals is dependent on a person's genotype. It's impossible at this time to identify the different genotypes that make up a study group, but it is important to remember that any study is going to contain and reflect a broad variety of genotypes, and that is going to have some impact on the results, she says. Just to muddy the research waters further, a brand new analysis of the ongoing Nurses' Health Study at Harvard now indicates that fruits and vegetables are helpful for preventing cardiac disease, but apparently not cancer! With all of this in mind, Dr. Higdon's advice is as follows: Eat lots of fruits and vegetables because we know they are good for you. Include well-washed apples and their skin, which contains a healthy dose of flavonoids, and load your plate with cruciferous vegetables because they seem to be associated with decreased risk for some cancers. But avoid isolated plant chemicals such as the apple extracts that are cropping up in the marketplace now. Dr. Higdon reminds us once again that there are many nutrients and chemicals in foods and, most likely, they act in a synergistic manner. If you want to be sure you're getting all the health benefits, eat fruits and vegetables whole -- lots of them and often.


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